Long-term wear electrode

ABSTRACT

An electrode for use with a therapeutic current delivery system can include a flexible, water vapor-permeable, conductive adhesive material; a current dispersing element in contact with the conductive adhesive material; and a non-conductive, flexible, water vapor-permeable, electrically-insulating top layer provided in contact with the current dispersing element. The current dispersing element can be conductive at least laterally along a plane of the electrode. The conductive adhesive material can be conductive in a direction substantially orthogonal to the plane of the electrode and semi-conductive in a direction substantially lateral to the plane of the electrode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/129,204 entitled “Long-Term Wear Electrode”, filed Mar. 6, 2015,the disclosure of which is hereby incorporated in its entirety byreference.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The present disclosure is directed to a wearable electrode for thedelivery of therapeutic electrical current, using such an electrode,where the electrode is both breathable and waterproof, and with theconductive properties to be able to support the efficacious delivery ofhigh current electrical therapy.

Description of Related Art

Cardiac arrhythmias, such as ventricular fibrillation and ventriculartachycardia, are electrical malfunctions of the heart, in which regularelectrical impulses in the heart are replaced by irregular, rapidimpulses. These irregular, rapid impulses can cause the heart to stopnormal contractions, thereby interrupting blood flow therethrough. Suchan interruption in blood flow can cause organ damage or even death.

Normal heart contractions, and thus normal blood flow, can be restoredto a patient through application of electric shock. This procedure,which is called defibrillation, has proven highly effective at treatingpatients with cardiac arrhythmias, provided that it is administeredwithin minutes of the arrhythmia. Portable, wearable defibrillatorsystems have been developed which monitor a patient's cardiac activity,detect arrhythmias, and provide defibrillation electric shocks torestore normal heart contractions and blood flow.

Various other pathophysiological conditions may also be treated by thedelivery of therapeutic electrical current to physiologic tissues suchas the myocardium, nerves, or skeletal muscles using such methods astransthoracic cardiac pacing (TCP).

In the current state of the art, a so-called “dry” therapeutic electrodemay be employed where the conductive gel is stored and then deployed viaelectronically-activated gas pressure, much like an air-bag in a car,such as is manufactured by ZOLL Medical Corporation, Pittsburgh Pa. Inthis case, separate electrocardiogram (ECG) monitoring electrodes areused.

Alternatively, self-adhesive electrodes such as are used onconventional, non-wearable defibrillators may be employed. In this case,the electrodes are capable of performing both the functions of ECGmonitoring and defibrillation. The self-adhesive defibrillatorelectrodes of these systems can be large, e.g., 2-8 inches in diameter,and use vapor impermeable materials such as metal foils, hydrophilic,water saturated conductive hydrogels, and electrically insulating layersthat prevent the patient's expired vapor from the skin surface fromevaporating, eventually softening the epidermis and resulting indegradation of the structural integrity of the skin leading to sloughingand peeling of the skin when the electrode is removed after extendedwear. As a result, the patient's skin may become irritated which canlead to the patient being non-compliant with his/her treatment whenhe/she refuses to or can no longer wear the electrodes.

Also, the materials from which these electrodes are made and theadhesives that are used are not waterproof during bathing or showeringand do not conform well to the patient's body or movement. This resultsin the electrodes having to be replaced frequently, often on a dailybasis.

Thus, there is a need for an electrode that is less irritating to thepatient's skin that remains adhered to the patient's skin for a longertime period, for example, as long as two weeks. A vapor permeableself-adhesive wearable electrical therapy electrode would be desirableover the current art for reducing thickness and weight while at the sametime increasing patient comfort and increasing the duration ofcontinuous electrode wear.

SUMMARY OF THE DISCLOSURE

An electrode for use with a therapeutic current delivery system cancomprise: a flexible, water vapor-permeable, conductive adhesivematerial; a current dispersing element in contact with the conductiveadhesive material; and a non-conductive, flexible, watervapor-permeable, electrically-insulating top layer provided in contactwith the current dispersing element. The current dispersing element canbe conductive at least laterally along a plane of the electrode. Theconductive adhesive material can be conductive in a directionsubstantially orthogonal to the plane of the electrode andsemi-conductive in a direction substantially lateral to the plane of theelectrode.

In one example, the current dispersing element can be conductive in adirection orthogonal to the plane of the electrode. The water vaporpermeability of the electrode can be greater than 100 gm/m²/24 hours. Inone example, the therapeutic current delivery system can be adefibrillation system or a pacing system. In an example, the electrodecan be configured to deliver a defibrillation pulse. The defibrillationpulse can comprise a therapeutic pulse having an energy of at least 200joules. In another example, the electrode can be configured to deliverat least one pacing pulse. The pacing pulse can comprise a current pulsehaving a duration in a range of 10-40 ms and an amplitude of at least 50mAmps. The electrode can be configured to uniformly distribute currentto a patient.

In one example, the flexible, water vapor-permeable, conductive adhesivematerial can comprise a material selected from the group consisting ofan electro-spun polyurethane adhesive, a polymerized microemulsionpressure sensitive adhesive, an organic conductive polymer, an organicsemi-conductive conductive polymer, an organic conductive compound and asemi-conductive conductive compound, and combinations thereof. Inanother example, the flexible, water vapor-permeable, conductiveadhesive layer can comprise a material selected from the groupconsisting of poly(3,4-ethylene dioxitiophene), doped with poly(styrenesulfonate), (PEDOT:PSS) poly(aniline) (PANI), poly(thiopene)s, andpoly(9,9-dioctylfluorene co-bithiophen) (F8T2), and combinationsthereof. In an example, a thickness of the flexible, watervapor-permeable, conductive adhesive material can be between 0.25 and 50mils. In another example, the water vapor-permeable, conductive adhesivematerial can comprise conductive particles.

In one example, the current dispersing element can comprise a metallicwire mesh. The metallic wire mesh can comprise a metal selected from thegroup consisting of copper, tin, nickel, silver, gold, and combinationsthereof. In another example, the conductive, current dispersing elementcan comprise nickel-plated carbon-filled fibers. In one example, thecurrent dispersing element can be segmented.

In an example, a backing can be attached to the flexible, watervapor-permeable, conductive adhesive material. The backing can extendbeyond an outer surface of the electrode. In one example, a frame can beprovided on an outer surface of the non-conductive, flexible, watervapor-permeable, electrically-insulating top layer. The frame can bedisposed around the perimeter of the electrode.

In one example, a therapeutic current delivery system can comprise: atherapeutic current delivery device; at least one cable connectorconnected to the therapeutic current delivery device; and at least oneelectrode connected to the at least one cable connector. The at leastone electrode can comprise: a flexible, water vapor-permeable,conductive adhesive material; a current dispersing element in contactwith the conductive adhesive material; and a non-conductive, flexible,water vapor-permeable, electrically-insulating top layer provided incontact with the current dispersing element. The current dispersingelement can be conductive at least laterally along a plane of theelectrode. The conductive adhesive material can be conductive in adirection substantially orthogonal to the plane of the electrode andsemi-conductive in a direction substantially lateral to the plane of theelectrode. In one example, the cable connectors can be no more than 10inches long. In another example, the therapeutic current delivery devicecan be a defibrillation device, a pacing device, or a nerve stimulationdevice.

In another example, an electrode for use with a therapeutic currentdelivery system can comprise: a flexible, water vapor-permeable,conductive adhesive material; a current dispersing element in contactwith the conductive adhesive material to receive a therapeutic currentfrom a connector and distribute the therapeutic current over a plane ofthe electrode; and a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer in contact with the current dispersingelement. The conductive adhesive material is conductive in a directionsubstantially orthogonal to a plane of the electrode and semi-conductivein a direction substantially lateral to the plane of the electrode. Thewater vapor permeability of the electrode can be greater than 100gm/m2/24 hours.

In one example, an electrode for use with a therapeutic current deliverysystem can comprise a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer; and a flexible, watervapor-permeable, conductive adhesive material disposed on one side ofthe electrically-insulating top layer. The conductive adhesive materialcan be configured to provide conductive paths in both lateral andorthogonal directions to a plane of the electrode. The top layer can bein contact with the conductive adhesive material.

In one example, the electrode can be configured to deliver adefibrillation pulse. The defibrillation pulse can comprise atherapeutic pulse having an energy of at least 200 joules. In anotherexample, the electrode can be configured to deliver at least one pacingpulse. The pacing pulse can comprise a current pulse having a durationin a range of 10-40 ms and an amplitude of at least 50 mAmps.

In an example, the conductive adhesive material can comprise conductiveparticles distributed in a polymer material to provide the conductivepaths. The conductive adhesive material can be configured tosubstantially distribute a therapeutic current over the plane of theelectrode prior to delivery to a subject. In one example, the electrodecan further comprise a current dispersing element in contact with theconductive adhesive material. The current dispersing element can beconfigured to be conductive at least laterally along the plane of theelectrode. The water vapor permeability of the electrode can be greaterthan 100 gm/m²/24 hours.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and characteristics of the present disclosure,as well as the methods of operation and functions of the relatedelements of structures and the combination of parts and economies ofmanufacture, will become more apparent upon consideration of thefollowing description and the appended claims with reference to theaccompanying drawings, all of which form a part of this specification,wherein like reference numerals designate corresponding parts in thevarious figures. It is to be expressly understood, however, that thedrawings are for the purpose of illustration and description only andare not intended as a definition of the limit of the invention.

FIG. 1 is a front elevational view of a defibrillation system accordingto the present disclosure attached to a patient;

FIG. 2 is a top elevational view of one example of an apex electrodeaccording to the present disclosure having a segmented currentdispersing element;

FIG. 3 is a top elevational view of one example of an anterior electrodeaccording to the present disclosure having a segmented currentdispersing element;

FIG. 4 is an expanded view of the electrode of FIG. 2;

FIG. 5 is an expanded view of the electrode of FIG. 3;

FIG. 6 is a top elevational view of one example of an apex electrodeaccording to the present disclosure having a non-segmented currentdispersing element;

FIG. 7 is a top elevational view of one example of an anterior electrodeaccording to the present disclosure having a non-segmented currentdispersing element;

FIG. 8 is a photograph of an electro-spun polyurethane adhesive as usedfor the flexible, water vapor-permeable, conductive adhesive layer ofthe present disclosure;

FIG. 9 is a schematic of the apparatus used to make the electro-spunpolyurethane adhesive of FIG. 8;

FIGS. 10A and 10B are schematic representations of the equipment andset-up used to perform the two disclosed methods for measuring Z-axisimpedance;

FIG. 11 is a schematic cross-sectional view of an example of anelectrode according to the present disclosure;

FIG. 12 is an expanded view of an electrode according to the presentdisclosure; and

FIG. 13 is a schematic cross-sectional view of the electrode of FIG. 12.

DESCRIPTION OF THE DISCLOSURE

As used herein, spatial or directional terms, such as “inner”, “left”,“right”, “up”, “down”, “horizontal”, “vertical” and the like, relate tothe invention as it is described herein. However, it is to be understoodthat the invention can assume various alternative orientations and,accordingly, such terms are not to be considered as limiting. For thepurposes of this specification, unless otherwise indicated, all numbersexpressing quantities of ingredients, reaction conditions, dimensions,physical characteristics, and so forth used in the specification andclaims are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by the present invention. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include any and all sub-ranges betweenand including the recited minimum value of 1 and the recited maximumvalue of 10, that is, all subranges beginning with a minimum value equalto or greater than 1 and ending with a maximum value equal to or lessthan 10, and all subranges in between, e.g., 1 to 6.3, or 5.5 to 10, or2.7 to 6.1.

Biomedical electrodes (referred to herein as simply “electrodes”) may beused for defibrillating, pacing, cardioversion, and/or monitoring theactivity of a subject's heart. The electrodes disclosed herein aresuitable for use on human subjects or patients, although use onnon-human subjects is also contemplated. Examples of electrodes asdisclosed herein can be coupled with power sources and control logic todeliver electrical energy to a subject, to determine the timing, levels,and history of applied energy, and to process monitored or detected datafor analysis by, for example, a health care provider. Examples ofelectrodes as disclosed herein may be located proximate to the subject,for example, attached, connected, or coupled to the subject, at ananterior, posterior, lateral, or other location on the subject. Forexample, examples of electrodes as disclosed herein can be attached tothe subject's chest, back, side, head, abdomen, torso, thorax, or legs.In some examples, the electrodes disclosed are configured to be attachedto the subject proximate to the subject's heart.

In various instances, it may be desirable to provide non-invasiveexternally placed electrodes for an extended period of time to allow fordefibrillation, to pace the heart, and/or to monitor the heart of asubject, for example, while the subject is recovering from a heartattack, surgery, or other injury to the heart, while awaiting a hearttransplant, or to monitor and/or protect a subject at risk of syncope.In some prior art externally-attached biomedical electrodes, attachmentof the electrodes to the skin of a subject may result in skin irritationat the point of attachment within a relatively short period of timeranging, for example, from about a few hours to about a few days.Extended-wear electrodes in accordance with examples of the presentdisclosure are constructed of materials, for example, adhesive films andelectrically conducting materials, which can reduce the occurrence ofskin irritation and/or extend the time for which the electrode may becomfortably attached to the skin of a subject.

In some examples, extended-wear electrodes in accordance with thepresent disclosure may be worn continuously by a subject for a timeperiod in excess of, for example, three days, for a week or more, or forup to about two weeks or more without the subject experiencingsignificant skin irritation due to the attachment of the electrode tothe skin of the subject. As used herein “significant skin irritation” isdefined as corresponding to a skin irritation grading of one (a weaklypositive reaction usually characterized by mild erythema and/or drynessacross most of the treatment site) or more as set forth in Table C.1 ofAnnex C of AANI/AAMI/ISO standard 210993-10:2010 when electrodes aretested on human subjects in accordance with the method set forth in thisstandard. As used herein, the terms “long-term wear” or “extended-wear”refer to continuous or substantially continuous contact of an electrodewith the skin of a subject for a time period in excess of, for example,three days, for a week or more, or for up to about two weeks or more.The extended-wear electrodes disclosed herein can have the ability toapply a defibrillation charge to, or perform cardioversion on, a subjectwearing the electrodes and may, in addition, monitor and/or pace theheart of a subject. Examples of the electrodes disclosed herein may becompliant with the ANSI/AAMI DF80:2003 medical electrical equipmentstandard for the safety of cardiac defibrillators.

As discussed above, conventional electrodes using vapor impermeablematerials may trap vapor emanating from the surface of a patient's skin.The water vapor emanating from intact skin can be significant, on theorder of 240-1,920 g/m² per 24 hours [Thomas S. Handbook of WoundDressings. Macmillan: London, 1994]. In contrast, in some examples, theextended-wear electrodes in accordance with the present disclosure mayprovide for the passage of water vapor, for example, a patient's sweat,through the electrode to facilitate reduction in skin irritation, forexample when the electrode is used for “long-term wear” or“extended-wear” regimens. Extended-wear electrodes in accordance withthe present disclosure may exhibit a moisture vapor transmission rate(MVTR) of, for example, between about 600 g/m²/day and about 1,400g/m²/day when worn by a subject in an environment at room temperature(e.g., about 25° C.) and at a relative humidity of, for example, about70%.

In some systems, the defibrillator, TCP, or other device capable ofdelivering therapeutic electrical current may be incorporated into awearable device in which case such a device can continuously monitor thephysiologic status of the patient over an extended period of time ofhours, days, and even months. In such cases, the wearable therapeuticsystem can be configured to be light and comfortable enough for apatient to be able to sleep, walk, and engage in all the normal dailyactivities. In particular, the current-carrying electrodes for deliveryof the therapeutic electrical current may be configured such thatelectrical contact be made between the conductive element of theelectrode and the patient's skin at the time of delivery of thetherapeutic current, while at the same time be wearable for extendedperiods without damage to the patient's skin.

Extended-wear electrodes in accordance with examples of the presentdisclosure may provide one or more advantages over prior art electrodes,for example the ability to wear the electrodes for an extended period oftime may reduce the number of electrodes consumed over a given period oftime, reducing the cost associated with replacing electrodes which arenot suitable for use in extended-wear scenarios, for example, for timeperiods greater than about a week.

Discomfort of a subject associated with wearing the electrodes may bedecreased due to a reduction in skin irritation caused by theextended-wear electrodes as compared to conventional electrodes.Discomfort of a subject associated with wearing the electrodes may alsobe decreased due to a reduction in the number of times which anextended-wear electrode may need to be removed from the skin of thesubject or repositioned, resulting in possible damage to the underlyingskin, as compared to conventional electrodes. Further, accuracy ofmonitoring of the heart of a subject may be facilitated by the use ofextended-wear electrodes by keeping the monitoring electrodes in thesame position rather than replacing them and mounting them inpotentially different positions as may occur with electrodes whichshould be replaced frequently or repositioned due to the occurrence ofskin irritation.

Electrodes in accordance with some examples of the present disclosuremay be combined as part of a long-term wear device, for example, as partof known non-invasive bodily-attached ambulatory medical monitoring andtreatment devices, such as the Life Vest® Wearable CardioverterDefibrillator available from ZOLL Medical Corporation. Electrodes inaccordance with some examples of the present disclosure may be used insyncope monitoring and/or treatment devices such as described in U.S.patent application Ser. No. 13/907,406, titled SYSTEMS AND METHODS FORDETECTING HEALTH DISORDERS, the disclosure of which is incorporated byreference herein in its entirety.

As shown in FIG. 1, two electrodes 12, 14 may be connected to a wearabledefibrillator/monitor 16 via a cable harness 18 and cable connectors 20a, 20 b. The defibrillator/monitor 16 may communicate with theelectrodes 12, 14 to monitor the patient, provide pacing impulses to thepatient, and to transmit defibrillation energy to the patient. While awearable defibrillator/monitor 16 is described with reference to FIG. 1,this is not to be construed as limiting the present disclosure, as anysuitable therapeutic current delivery system may be utilized with theelectrodes 12, 14 disclosed herein, such as a pacing device or atranscutaneous electrical nerve stimulation device. If a defibrillationsystem is used, an energy setting can be in a range of 150-360 Joules.For example, the energy setting can be about 200 Joules. In someexamples, if a pacing device is used, an initial energy setting may beconfigured to have the device deliver through an electrode a 10-40 mscurrent pulse of energy at a current of at least 50 mAmps.

In one example, two electrodes 12, 14 may be used. An apex electrode 12is placed on the patient's left abdomen and back and an anteriorelectrode 14 is placed on the patient's upper right chest as shown inFIG. 1. The electrodes 12, 14 may be provided, for example, to applyelectrical treatment or shock, or may further comprise at least onesensing element 30 as shown in FIGS. 2-7. For example, the apexelectrode 12, shown in FIGS. 2, 4, and 6, can include, e.g., two sensingelements 30, and the anterior electrode 14, shown in FIGS. 3, 5, and 7,can include, e.g., one sensing element 30.

In one example, the electrodes 12, 14 can comprise a conductive, watervapor-permeable adhesive material that is configured to be positionedagainst the skin of a patient. The conductive adhesive material providesthe function of adhesion and conduction of current primarily in theZ-axis direction (orthogonal to the plane of the electrode). Theelectrodes 12, 14 can also comprise a current dispersing element suchas, but not limited to, a conductive mesh. The current dispersingelement provides the function of current dispersal in the X-Y directions(laterally, along the plane of the electrode) to ensure the currentdistribution is more uniform, thus preventing burning of the patient'sskin as a result of therapeutic current delivery that is uneven acrossthe face of the electrode and causing electrical current burns on thepatient. The electrodes 12, 14 can also comprise an outermost layer awayfrom the patient's skin. This layer provides the functions of electricalinsulation, preventing shocks to bystanders, and functions as awater-resistant or waterproofing layer so that the electrodes 12, 14 maybe worn in the shower or while bathing.

Referring to FIGS. 2-7, prior to application to the skin of the patient,each electrode 12, 14 comprises: at least one non-conductive, flexible,water vapor-permeable, electrically insulating top layer 22 thatprovides, e.g., protection from short circuiting of the electrodeagainst adjacent conductive objects in the vicinity of the patientduring a defibrillation shock; a current dispersing element 24 a, 24 b,e.g., comprising or made from a flexible, conductive, watervapor-permeable mesh providing enhanced conductivity and mechanicalsupport; a flexible, water vapor-permeable, conductive adhesive material26 for contact with the patient's skin; and optionally a removablebacking 28.

The flexible, water vapor-permeable, conductive adhesive material 26 forcontact with the patient's skin may comprise or be made from materialsincluding, but not limited to, a spun adhesive polymer such as anelectro-spun polyurethane adhesive, for example, as described in Khil etal., “Electrospun Nanofibrous Polyurethane Membrane as Wound Dressing”,Journal of Biomedical Materials Research Part B: Applied Biomaterials,67(2), pp. 675-679, 2003, the disclosure of which is incorporated byreference herein in its entirety, and as shown in FIG. 8.

In one example, such electrospun polyurethane adhesive can be producedusing an electrospinning setup shown in FIG. 9. Polymer solutions areinjected through a syringe 60. A positive electrode 62 is inserted intothe solution and a rotational collector 64 is placed at an appropriatedistance from the tip of the syringe 60 to act as a grounded counterelectrode. As an electrical potential is applied, a polymer stream 66 iscreated. The polymer stream 66, formed by electrical forces, follows acomplicated stretching and looping pattern as it solidifies. Theresulting fibers 68 are collected on the rotational collector 64 toproduce a sheet of membrane.

In order to achieve conductive qualities in the flexible, watervapor-permeable, conductive adhesive material 26, conductive particlesmay be injected into the housing containing the apparatus of FIG. 9. Theconductive particles may be microscopic or nano-scale particles orfibers of materials, including but not limited to, one or more of carbonblack, silver, nickel, graphene, graphite, carbon nanotubes, and/orother conductive biocompatible metals such as aluminum, copper, gold,and/or platinum. The conductive particles may be sprayed into thehousing where the electrospinning is occurring and are charged with theopposite polarity as the polymer stream 66. The conductive particles areattracted to and bonded to the polymer stream 66 resulting in aconductive adhesive sheet.

Alternatively, the flexible, water vapor-permeable, conductive adhesivematerial 26 may be fabricated via such known means for creatingpolymerized microemulsion pressure sensitive adhesives as described inU.S. Pat. No. 5,670,557, the disclosure of which is incorporated byreference herein in its entirety. During the mixing process of themicroemulsion, the previously described conductive particles are addedand dispersed into the microemulsion. The conductive particles mayfurther be treated to preferentially attract to one or the other of thetwo domains of the microemulsion. Thus, if one domain is designed toevaporate, leaving a microporous structure, the conductive particleswill reside in the evaporating layer, and then eventually coat theinside walls of the porosities in the final film. Alternatively, anelectroplating process can be used to plate copper, silver chloride, orother metal onto the inner walls of the microporous structure.

Alternatively, an appropriate organic conductive or semi-conductivepolymer or other compound, such as poly(3,4-ethylene dioxitiophene),doped with poly(styrene sulfonate), (PEDOT:PSS) poly(aniline) (PANI),poly(thiopene)s like poly(3-hexylthiophene) (P3HT) andpoly(9,9-dioctylfluorene co-bithiophen) (F8T2) can be used to preparethe conductive adhesive. Such polymers can be printed as a flexible,water vapor-permeable, conductive adhesive layer using such methods asinkjet printing, screen printing, offset printing, flexo printing, andgravure printing.

The flexible, water vapor-permeable, conductive adhesive material 26 isdesigned to be sufficiently conductive in a direction substantiallyorthogonal to a plane of the electrode (i.e., in the Z-axis) by, e.g.,controlling both its thickness and a density and shape of the conductiveparticles that are dispersed in the adhesive polymer matrix. Compositematerial properties, which result when conductive particles aredispersed into a polymer matrix, may be influenced by the particlevolume fraction. The conductive paths are formed by metal particles. Atcritical concentration, a connected chain network of particles firstappears in the system. As the particle concentration is increased, thefraction of particles in this network increases. Such a network cancontribute to the major conduction process. This is known as PercolationTheory of conductive adhesives. Several factors are known to affect themagnitude of the threshold volume fraction, such as particle sizedistribution, particle shape, and pre-treatment of the particle. For anadhesive that is preferentially conductive in the Z-direction, thevolume loading of conductive particles can be on the order of 5-25% byvolume. The geometry of the conductive particles themselves may beapproximately spheroidal, flake, or needle-like. The size of theconductive particles may be in the range of, though not limited to,about 1 to about 100 μm. While the conductive adhesive layer 26 mayrange in thickness from 0.25 to 50 thousandths of an inch or more, insome implementations the thickness is about 1 to 10 mils. The conductiveparticles may also be nano-sized particles. The conductive particles maybe pre-treated with an etchant such as phosphoric acid, and/or coatedwith an interfacial coupling agent such as a silane. The silane may bedesigned to provide some level of semi-conductivity or conductivity.Alternative coupling agents such as thiols, carboxylate, or others mayalso be used. Such adhesives are discussed in detail in Sancaktar, E. etal., “Electrically Conductive Epoxy Adhesives”, Polymers, vol. 3, pp.427-466, 2011, the disclosure of which is incorporated by referenceherein in its entirety.

The current dispersing elements 24 a, 24 b may comprise a flexible,conductive mesh that can provide enhanced conductivity and mechanicalsupport for the structure or any other suitable flexible, conductivematerial. Without it, the flexible, water vapor-permeable, conductiveadhesive material 26 can be insufficiently conductive in the lateral(X-Y) direction to carry defibrillation current through the cableconnectors 20 a, 20 b to the patient without substantial current orvoltage degradation. The mesh may be a simple metallic mesh composed,for example, of copper, tin, nickel, silver, gold, and/or otherconductive, biocompatible material as discussed in detail above. Thegauge and weave of the mesh are designed to be conformable to the body.Generally, the gauge of the wire is higher than 22 AWG (smallerdiameter, less than 0.0253 inches). In some examples, the gauge isaround 60 AWG, with the mesh opening spaces making up at least 30% ofthe mesh surface area. In some examples, the mesh occupies less than 15%of the surface area of a plane defined by the mesh. In other examples,the mesh may comprise nickel-plated carbon-filled fibers. The currentdispersing elements 24 a, 24 b may be formed into the conductiveadhesive material 26, during the polymerization of the conductivepre-polymer solution, thereby creating a single structure thatincorporates the functionality of both the current dispersal element 24a, 24 b and the adhesive 26. In addition, the conductive adhesivematerial 26 is not required to be a sheet or continuous film interposedbetween the current dispersing elements 24 a, 24 b and the patient'sskin. In one example, the conductive adhesive material 26 can be sprayedor applied as a coating onto the current dispersing elements 24 a, 24 b.

In one example, the current dispersing elements 24 a, 24 b can bepositioned between the flexible, water vapor-permeable, conductiveadhesive layer 26 and a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer 22 as discussed in greater detailhereinafter.

In some examples, the current dispersing elements 24 a, 24 b is adheredto the conductive adhesive layer 26 by positioning the currentdispersing elements 24 a, 24 b in contact with or facing engagement withat least a portion of the adhesive portion, such that at least thecontacting portion of the current dispersing elements 24 a, 24 b isadhered to the adhesive material 26. In some examples, the optionalremovable backing 28 can be adjacent to the adhesive material 26 priorto contact with the current dispersing elements 24 a, 24 b, and heatand/or pressure can be applied to form an adhesive bond between thecurrent dispersing elements 24 a, 24 b and the adhesive material 26. Theadhesive material itself may be designed to bond self-adhesively to theother layers in contact with it. Additional current dispersing materialsmay be interposed between the current dispersing elements 24 a, 24 b andthe conductive adhesive material 26. The additional current dispersingmaterial may take the form of sprayed conductive nano- ormicro-particles such as carbon black or nickel flake. For example, thiscan improve current uniformity in the case when the current dispersingelement is made of a metallic wire mesh.

The top layer 22 is generally non-conductive, flexible, watervapor-permeable, electrically-insulating, and optionally at leastsubstantially liquid-impermeable or waterproof. The non-conductiveflexible, water-vapor permeable, electrically-insulating top layer 22may comprise or consist of polyurethane, such as Tegaderm™ polyurethanefilm (available from 3M), Opsite™ polyurethane film (available fromSmith & Nephew), or Hydrofilm™ polyurethane film (available from HartmanUSA). The top layer 22 can provide some protection from defibrillationcurrent inadvertently shocking someone close to the patient. Inaddition, where the top layer 22 is waterproof, the extended-wearelectrodes disclosed herein may be worn when the user is showering.

With respect to the top layer 22, as used herein, the term“non-conductive” means impedance in excess of 1000 ohms by the Z-axisImpedance Measurement Method 1 discussed hereinafter. With respect tothe top layer 22, as used herein, the term “electrically-insulating”means using the test set-up of Z-axis Impedance Measurement Method 1discussed hereinafter, then applying 120+/−10 VDC, 15 second duration,with leakage current not to exceed 100 microamps. With respect to thetop layer 22, as used herein, the term “liquid-impermeable” meanswaterproof per AATCC 127-2014. In some embodiments, the top layer 22 maybe composed of Tegaderm, and the top layer 22 contains its own adhesivewith which the Tegaderm is affixed to the underlayers of the currentdispersing elements 24 a, 24 b, or alternatively may be a GORE-TEX® PTFEfilm that is adhesively affixed to the underlayers. The top layer 22 insome implementations has a larger diameter than the other sublayers,thus providing an adhesively-sealed perimeter that provides bothwaterproofing as well as enhanced electrical insulation.

In an example, the electrodes 12, 14 are a laminate structure with theadhesive material 26, the current dispersing elements 24 a, 24 b, andthe top layer 22 being aminated together. In such an example, theflexural rigidity of the electrodes 12, 14 is, by necessity, is equal toor greater than the flexural rigidity of each individual components. Theoverall flexural rigidity of the electrodes 12, 14 can be less than 40grams/cm², as measured using the ASTM D1388-14, “Standard Test Methodfor Stiffness of Fabrics”. This standard requires the electrode 12, 14to be slid at a specified rate in a direction parallel to its longdimension until its leading edge projects from the edge of a horizontalsurface. The length of the overhang is measured when the tip of thespecimen is depressed under its own mass to a point where the linejoining the top to the edge of the platform makes a 41.5° angle with thehorizontal. From this measured length, the bending length and flexuralrigidity are calculated using the following equations.c=O/2where:

c=bending length, mm; and

O=length of overhang.G=1.421×10⁻⁵ ×W×c ³where:

G=flexural rigidity;

W=fabric mass per unit area; and

c=bending length.

In addition, in one example, the vapor permeability of the electrodes12, 14 is greater than 100 gram/meter²/24 hours, as measured by suchvapor transmission standards of ASTM E-96-80 (Version E96/E96M-13),using either the “in contact with water vapor” (“dry”) or “in contactwith liquid” (“wet”) methods discussed in greater detail hereinafter.

The electrodes 12, 14 may be used to deliver other forms of high-powertherapeutic electrical current to the patient other than defibrillation,for instance external TCP used to keep a bradycardic heart beating at anormal rate or other cardiac conditions. “High power” is here consideredan electrical pulse in excess of 1 Joule or 20 milliamps.

The present disclosure is not limited to any particular shape for theelectrode, or of the components thereof, and any one or more componentsof an electrode in accordance with the present disclosure may havedifferent shapes than those illustrated. For example, the currentdispensing element 24 a can be segmented with a low surface area andhigh perimeter as compared to a circular or square electrode and asshown in FIGS. 2-5 where the current dispersing element 24 a takes aclover shape having four circular segments. The overall size and shapeof the current dispersing element 24 a may differ from that of theadhesive material 26 and/or the top layer 22. Overall area for theelectrode when used in pacing or defibrillation can be about 25-200inches².

Alternatively, the current dispersing element 24 b may be non-segmentedand may be oval, triangular, square, pentagonal, or any other shapedesired. As shown in FIGS. 6 and 7 for example, the current dispersingelement 24 b is a single, large circle.

A small area of the non-conductive, flexible, water vapor-permeable,electrically-insulating top layer 22 is relieved to expose a small area,of approximately 0.25 square inches±90%, of the current dispersingelements 24 a, 24 b. Wires 32, 34 (shown in FIG. 1) of the cableconnectors 20 a, 20 b are attached to the electrodes 12, 14 by aconnector, such as a rivet or clamp mechanism directly to the currentdispersing elements 24 a, 24 b, and an additional small piece(s) ofadhesive material 26 may be used to cover any small regions of exposedconductive surfaces in the area of the attachment.

In some examples, backing 28 can be attached to the adhesive material26. The backing 28 extends beyond the outer surfaces of the electrodes12, 14 in order to provide an area for the user to grasp the backing 28when removing it from the electrodes 12, 14 for placement on thepatient. The backing 28 may be made from liners made of or coated withpolyethylene, polypropylene, and fluorocarbons and silicone coatedrelease papers or polyester films, for example.

If present, the sensing elements 30 can be positioned between theflexible, water vapor-permeable, conductive adhesive material 26 and thenon-conductive, flexible, water vapor-permeable, electrically-insulatingtop layer 22. The sensing elements 30 may be made of a core plastic ormetal substrate element that is coated with a thick-film polymericcompound filled with a conductive Ag/Ag/Cl metallic filler, as iscurrently used by most ECG electrode manufacturers such as Biodetek(Pawtucket, R.I.). Alternatively, the sensing function may be providedby the electrodes 12, 14 themselves, and the separate sensing element iseliminated.

Both the current dispersing elements 24 a, 24 b and the sensing element30 may include a portion which extends through the top layer 22 tocontact an electrical connector 38 (shown in FIG. 1). The electricalconnector 38 may include a protrusion that acts as a snap for connectionof the wires 32, 34 of the cable connectors 20 a, 20 b or may take anyother suitable form including, but not limited to a structure suitablefor attaching an alligator clip. Alternatively, the wires 32, 34 of thecable connectors 20 a, 20 b may be directly hard wired to the currentdispersing elements 24 a, 24 h and/or the sensing element 30 asdescribed above.

Alternatively, the current dispersing elements 24 a, 24 b could be usedboth for defibrillation and sensing and the sensing elements 30 could beeliminated.

As can be seen in FIGS. 2-7, the top layer 22 can be configured tocompletely cover the current dispersing elements 24 a, 24 b and thesensing element 30. However, the surface area of the top layer 22 isminimized as much as possible so that the amount of the patient's skinthat is subjected to possible irritation is minimized. Along theselines, it can be seen when comparing FIGS. 2, 4, and 6 to FIGS. 3, 5,and 7, that when using the segmented current dispersing element 24 a,the sensing elements 30 can be moved closer to the center of theelectrodes 12, 14 than when using the non-segmented current dispersingelement 24 b, thus reducing the overall area of the electrodes 12, 14.

A frame 40 may be provided on the outer surface of the top layer 22 togive some structural stability to the electrodes 12, 14 after beingremoved from the backing 28 and before being placed on the patient'sskin. The frame 40 may cover the entire surface of the top layer or, asshown in FIGS. 2-7, may be disposed only around the perimeter of theelectrodes 12, 14 extending a short distance toward the center of theelectrodes 12, 14. The frame 40 may include any number or shape ofextensions or tabs 42 that extend beyond the perimeter of the electrodes12, 14 to assist in removal of the electrodes 12, 14 from the backing 28for placement on the patient's skin, and the frame 40 from theelectrodes 12, 14 after the electrodes 12, 14 have been placed on thepatient's skin. The frame 40 may also include one or more perforationsor score lines to assist in its removal.

In use, the backing 28 is peeled from the electrodes 12, 14. Theelectrodes 12, 14 are placed on the patient's skin and pressed intoplace. The frame 40 is then removed from the electrodes 12, 14.

The electrodes 12, 14 can be capable of undergoing, without failure, atleast one current pulse delivered by a current generating device, suchas a defibrillator or pacemaker, the pulse being of at least 1millisecond in duration and 200 volts peak and at least 1 Ampere peak.

Vapor Permeability

As mentioned hereinabove, the electrodes 12, 14 are vapor permeable toallow the electrodes 12, 14 to be worn continuously by the patient formore than 24 hours. Vapor permeability of the complete electrodeassembly is greater than 100 gram/m²/24 hours, as measured by such vaportransmission standards of ASTM E-96-80 (Version E96/E96M-13), usingeither the “in contact with water vapor” (“dry”) or “in contact withliquid” (“wet”) methods. Such test methods are described in U.S. Pat.No. 6,548,727, the disclosure of which is incorporated by referenceherein in its entirety. These test methods are discussed in additionaldetail below.

Moisture Vapor Transmission Rate (Standard “Dry” Method)

A sample (3.5-cm diameter) is placed between adhesive-containingsurfaces of two foil adhesive rings, each having a 2.54-cm diameterhole. The holes of each ring are carefully aligned. Finger pressure isused to form a foil/sample assembly that is flat, wrinkle-free, and hasno void areas in the exposed sample.

A 120-mid glass jar is filled to the halfway level with deionized water.The jar is fitted with a screw-on cap having a 3.8-cm diameter hole inthe center and a 4.45-cm diameter rubber washer having a 2.84-cmdiameter hole in its center. The rubber washer is placed on the lip ofthe jar and the foil/sample assembly is placed on the rubber washer. Thelid is then screwed loosely on the jar.

The assembly is placed in a chamber at 38° C. and 20% relative humidityfor four hours. At the end of four hours, the cap is tightened insidethe chamber so that the sample is level with the cap (no bulging) andthe rubber washer is in the proper seating position.

The foil/sample assembly is then removed from the chamber and weighedimmediately to the nearest 0.01 gram (initial weight W1). The assemblyis then returned to the chamber for at least 18 hours, after which it isremoved and weighed immediately to the nearest 0.01 gram (final weightW2). The moisture vapor transmission (MVTR) in grams of water vaportransmitted per square meter of sample area in 24 hours is calculatedaccording to the following formula (where “T1” refers to exposure timein hours):“Dry”MVTR=(W1−W2)(4.74×104)÷T1

Three measurements are taken and averaged, and the “dry” MVTR value isreported as grams/m²/24 hrs.

Moisture Vapor Transmission Rate (Inverted “Wet” Method)

The inverted “Wet” Moisture Vapor Transmission Rate (Standard “Dry”Method) (MVTR) is measured using the following test procedure. Afterobtaining the final “dry” weight (W2) as described for the “dry” MVTRprocedure, the assembly is returned to the chamber (38° C. and 20%relative humidity) for at least 18 additional hours with the sample jarsinverted so that the deionized water is in direct contact with the testsample. The sample is then removed from the chamber and weighed to thenearest 0.01 gram (final “Wet” weight, W3). The inverted “Wet” MVTR ingrams of water vapor transmitted per square meter of sample area in 24hours is calculated according to the following formula (where “T2”refers to exposure time in hours):Inverted“Wet”MVTR=(W2−W3)(4.74×104)÷T2

Three measurements are taken and averaged, and the “wet” MVTR value isreported as g/m²/24 hrs.

Peel Adhesion

The electrode 12, 14 also meets the peel adhesion test established bythe Pressure Sensitive Adhesive Tape Council of Chicago, Ill. (“PSTC”):namely, PSTC-1 (11/75) entitled “Peel Adhesion for Single Coated Tapes180° Angle”, (“PSTC-1 Test”), the disclosure of which is incorporated byreference herein in its entirety. This test is described in U.S. Pat.Nos. 5,670,557, 4,952,650, and 4,833,179, the disclosures of which areincorporated by reference herein in their entireties. The PSTC-1 Testdetermines peel adhesion as the force required to remove a pressuresensitive adhesive tape from a panel or its own backing at a specifiedangle and speed. The electrode 12, 14 has a peel adhesion of at least 3N/100 mm as determined by the PSTC-1 Test. This test method is discussedin additional detail below.

Peel Adhesion Test

Peel adhesion is the force required to remove a coated flexible sheetmaterial from a test panel measured at a specific angle and rate ofremoval. This force is expressed in Newtons per 100 mm (N/100 mm) widthof coated sheet. A 12.5 mm width of the coated sheet is applied to thehorizontal surface of a clean glass test plate with at least 12.7 linealcm in firm contact. A hard rubber roller is used to apply the strip. Thefree end of the strip is doubled back nearly touching itself, so theangle of removal will be 180°. The free end is attached to the adhesiontester scale. The glass test plate is clamped in the jaws of a tensiletesting machine which is capable of moving the plate away from the scaleat a constant rate of 2.3 meters per minute. The scale reading inNewtons is recorded as the tape is peeled from the glass surface. Thedata is recorded as the average value of the range of numbers observedduring the test.

Impedance

Impedance of the disclosed electrode may be measured in three differentways as described in “3M™ Electrically Conductive Cushioning Gasket TapeECG-8035/ECG-8055/ECG-8075”, Technical Data, February, 2010, thedisclosure of which is incorporated by reference herein in its entirety.

Z-Axis Impedance Measurement Method 1

As shown in FIG. 10A, a 25.4 mm×25.4 mm sample is placed between two25.4 mm×25.4 mm gold plated brass probes, and the sample assembly isplaced under a 1 kg load. The impedance is measured using a 60 seconddwell time and reported in ohms (Ω). Using this method, the Z-axisimpedance of the conductive adhesive material 26 is less than 25 ohms.

Z-Axis Impedance Measurement Method 2

As shown in FIG. 10B, a 10 mm×10 mm sample is placed between two goldplated brass probes. The impedance is measured using a 60 second dwelltime without any load and reported in ohms (Ω). Using this method, theZ-axis impedance of the conductive adhesive material 26 is less than 50ohms. Satisfying these two test methods can constitute “conductive” inthe Z-axis direction.

Surface Impedance Measurement

The surface of a sample is contacted by a 25 mm×25 mm Cu plate for 10seconds and the impedance is measured and reported in ohms sq. (Ω/□).Using this method, the surface impedance of the conductive adhesivematerial 26 is less than 100 ohms/sq.

X-Y Axis Impedance Measurement

A 25.4 mm×75 mm wide strip of conductive adhesive material is cut out.25 mm of the length is adhered to one of the 25.4 mm wide gold platedbrass probes of FIG. 10A, and then the upper probe is placed on top asin the figure. At the other end of the strip, a 25 mm is adhered in thesame fashion to a second pair of probes. Impedance is then measuredalong the length of the strip. Using this method, the impedance shallexceed 5 ohms. Satisfying this test condition constitutes“semi-conductive” in the X-Y directions.

The same X-Y axis Impedance Measurement is performed for the currentdispersing element. Using this method, the impedance shall be less than5 ohms. Satisfying this test condition shall constitute “conductive” inthe X-Y directions. In some examples, the current dispersing element isalso conductive in the Z-direction such that the current dispersed inthe X-Y direction is guided to the conductive adhesive 26 and to thepatient.

For the case when the electrodes are to be used for defibrillation, theimpedance of the electrodes when measured using the AAMI DF-2 largesignal impedance test shall not exceed 10 ohms.

With reference to FIG. 11, for example, current from the cable connector20 a is provided to the current dispersing elements 24 a, 24 b, which isconductive at least laterally along the plane of the electrodes 12, 14as denoted by arrows A₁. Accordingly, the current dispersing elements 24a, 24 b are conductive at least in the X-Y direction and distribute anelectric current over a plane of the electrode. Further, at a pluralityof points along the current dispersing elements 24 a, 24 b, the currentcan move downward in the Z-axis direction. Accordingly, the currentdispersing elements 24 a, 24 b are conductive in a direction orthogonalto the plane of the electrode or conductive in the Z-axis direction asdenoted by arrows A₂ in FIG. 11. The conductive adhesive material 26 ofthe electrodes 12, 14 is conductive in a direction substantiallyorthogonal to the plane of the electrode 12 as denoted by arrows A₂.Accordingly, the conductive adhesive material 26 is conductive in theZ-axis direction. In addition, the conductive adhesive material 26 isalso semi-conductive in a direction substantially laterally along theplane of the electrodes 12, 14 as denoted by arrows A₃. Accordingly, theconductive adhesive material 26 is semi-conductive in the X-Ydirections.

With reference to FIG. 12, another example of an electrode 112 comprisesat least one non-conductive, flexible, water vapor-permeable,electrically insulating top layer 122 that provides, e.g., protectionfrom short circuiting of the electrode against adjacent conductiveobjects in the vicinity of the patient during a defibrillation shock; aflexible, water vapor-permeable, conductive adhesive material 126 forcontact with the patient's skin; and optionally a removable backing 128.

In this example, the conductive adhesive material 126 can compriseconductive particles distributed in a polymer material to provideconductive paths. Accordingly, the conductive adhesive material 126 canbe manufactured from any of the materials described hereinabove withreference to conductive adhesive material 26.

In addition, the top layer 122 can be generally non-conductive,flexible, water vapor-permeable, electrically-insulating, and optionallyat least substantially liquid-impermeable or waterproof. Thenon-conductive flexible, water-vapor permeable, electrically-insulatingtop layer 122 may comprise or consist of polyurethane, such as Tegaderm™polyurethane film (available from 3M), Opsite™ polyurethane film(available from Smith & Nephew), or Hydrofilm™ polyurethane film(available from Hartman USA). The top layer 122 can provide someprotection from defibrillation current inadvertently shocking someoneclose to the patient. In addition, where the top layer 122 iswaterproof, the extended-wear electrodes disclosed herein may be wornwhen the user is showering.

With reference to FIG. 13, for example, the conductive adhesive material126 is configured to substantially distribute a therapeutic current froma therapeutic current delivery device (not shown) over the plane of theelectrode 112 prior to delivery to a subject. Current from a cableconnector 120 connected between the therapeutic current delivery deviceand the conductive adhesive material 126 is provided, the conductiveadhesive material 126 as denoted by arrows B₁. Since the conductiveadhesive material 126 includes a plurality of conductive particlesdistributed in a polymer material, the conductive adhesive material 126is conductive in both lateral (denoted by arrows B₂ and B₄) andorthogonal directions (denoted by arrows B₃) to a plane of theelectrode. For example, the conductive adhesive material 126 can beconfigured by, e.g., controlling both its thickness and a density andshape of the conductive particles that are dispersed in the adhesivepolymer matrix, to provide conductive paths in both the lateral andorthogonal directions relative to the plane of the electrode. In someexamples, the conductive adhesive layer can be applied as a coating tothe electrically-insulating top layer. Accordingly, the currentdistribution is uniform, thus preventing burning of the patient's skinas a result of therapeutic current delivery that is uneven across theface of the electrode and causing electrical current burns on thepatient. In some implementations, a current dispersing element disposedin a similar manner as described in connection with FIG. 11 can also beincluded to improve current dispersing qualities of the electrode.

Electrodes in accordance with the present disclosure may includeadditional features not illustrated, for example, adhesive layersbonding the various components of the electrode together, labeling, amechanism for holding the electrical conductor in place and inelectrical contact with the conductive element, and/or packaging.Exemplary additional features are disclosed in U.S. patent applicationSer. No. 13/079,336, titled BIOMEDICAL ELECTRODE, the disclosure ofwhich is incorporated by reference herein in its entirety. Components ofelectrodes in accordance with examples of the present disclosure may beformed from materials having certain desirable properties. For example,an electrode may be formed of materials that render it radiolucent orradiotransparent, as disclosed in co-pending U.S. patent applicationSer. No. 13/079,336. Further, electrodes in accordance with the presentdisclosure may communicate wirelessly with other circuitry.

Electrodes in accordance with the present disclosure may besubstantially flat. For example, the electrodes may have a flat profilethat is not noticeable or is minimally noticeable when attached to thesubject, under the subject's clothes. The electrodes may also besubstantially flexible. For example, the electrodes may conform to thecontours of the subject's body during initial attachment to the subject,and may conform to body positioning changes when the subject is inmotion. The electrodes can also be substantially devoid of rigidcomponents, such as hard snaps, connectors, and rigid plates. Forexample, the electrodes may be devoid of hard rigid substances that maycause uncomfortable pressure points when a subject with the electrodesattached to his/her body is in a prone, prostrate, supine, or lateralposition with the electrodes pressed against an object, such as a bed,couch, medical examining table, clothes, or medical equipment.

As shown in FIG. 1, the cable harness 18, which is connected to thedefibrillator/monitor 16, includes three sensing element wires, twocurrent dispersing element wires, and two ground wires. Two sensingelement wires, one current dispersing element wire, and one ground wireare contained in an apex composite cable 44 of the cable harness 18having an apex connector 46 for connecting the apex composite cable 44to the apex electrode cable connector 20 a, and one sensing elementwire, one current dispersing element wire, and one ground wire arecontained in an anterior composite cable 48 of the cable harness 18having an anterior connector 50 for connecting the anterior compositecable 48 to the anterior electrode cable connector 20 b. The apexelectrode cable connector 20 a includes a connector 52 adapted forconnection to the apex connector 46 of the apex composite cable 44 andthree individual wires 32 each having a connector, such as a snap or analligator clip, for connecting to the electrical connectors 38 of theapex electrode 12, and the anterior electrode cable connector 20 bincludes a connector 56 for connection to the anterior connector 50 ofthe anterior composite cable 48 and two individual wires 34 each havinga connector for connecting to the electrical connectors 38 of theanterior electrode 14. The connectors 46, 50 of the cable harness 18 andthe connectors 52, 56 of the apex electrode cable connector 20 a and theanterior electrode cable connector 20 b may have structures, markings,colors, and the like so that it is clear which connector 46, 50 of thecable harness 18 is to be connected to the apex electrode cableconnector 20 a and which connector 46, 50 of the cable harness 18 is tobe connected to the anterior electrode cable connector 20 b and mayfurther include structure that only allows the proper connection to bemade.

The individual wires 32, 34 of the apex electrode cable connector 20 aand the anterior electrode cable connector 20 b may alternatively behard wired to the electrical connectors 38 of the electrodes 12, 14.

The length of the apex electrode cable connector 20 a and the anteriorelectrode cable connector 20 b should be minimized, especially when theyare hardwired to the electrodes 12, 14, so that they provide as littleforce on the thin flexible electrodes 12, 14 during placement on thepatient's skin as possible. For example, the apex electrode cableconnector 20 a and the anterior electrode cable connector 20 b shouldhave a maximum length no longer than 10 inches and preferably, no longerthan 9 inches.

Although the disclosure has been described in detail for the purpose ofillustration based on what is currently considered to be the mostpractical and preferred examples, it is to be understood that suchdetail is solely for that purpose and that the disclosure is not limitedto the disclosed examples but, on the contrary, is intended to covermodifications and equivalent arrangements that are within the spirit andscope of the appended claims. For example, it is to be understood thatthe present disclosure contemplates that, to the extent possible, one ormore features of any example can be combined with one or more featuresof any other example.

The disclosure claimed is:
 1. An electrode for use with a therapeuticcurrent delivery system, comprising: a flexible, water vapor-permeable,conductive adhesive material; a current dispersing element in contactwith the conductive adhesive material; and a non-conductive, flexible,water vapor-permeable, electrically-insulating top layer provided incontact with the current dispersing element; wherein the currentdispersing element is conductive at least laterally along a plane of theelectrode; and wherein the conductive adhesive material is conductive ina direction substantially orthogonal to the plane of the electrode andsemi-conductive in a direction substantially lateral to the plane of theelectrode.
 2. The electrode of claim 1, wherein the current dispersingelement is conductive in a direction orthogonal to the plane of theelectrode.
 3. The electrode of claim 1, wherein the water vaporpermeability of the electrode is greater than 100 gm/m²/24 hours.
 4. Theelectrode of claim 1, wherein the therapeutic current delivery system isa defibrillation system.
 5. The electrode of claim 1, wherein thetherapeutic current delivery system is a pacing system.
 6. The electrodeof claim 1, wherein the electrode is configured to deliver adefibrillation pulse.
 7. The electrode of claim 6, wherein thedefibrillation pulse comprises a therapeutic pulse having an energy ofat least 200 joules.
 8. The electrode of claim 1, wherein the electrodeis configured to deliver at least one pacing pulse.
 9. The electrode ofclaim 8, wherein the pacing pulse comprises a current pulse having aduration in a range of 10-40 ms and an amplitude of at least 50 mAmps.10. The electrode of claim 1, wherein the electrode is configured touniformly distribute current to a patient.
 11. The electrode of claim 1,wherein the flexible, water vapor-permeable, conductive adhesivematerial comprises a material selected from the group consisting of anelectro-spun polyurethane adhesive, a polymerized microemulsion pressuresensitive adhesive, an organic conductive polymer, an organicsemi-conductive conductive polymer, an organic conductive compound and asemi-conductive conductive compound, and combinations thereof.
 12. Theelectrode of claim 1, wherein the flexible, water vapor-permeable,conductive adhesive layer comprises a material selected from the groupconsisting of poly(3,4-ethylene dioxitiophene), doped with poly(styrenesulfonate), (PEDOT:PSS) poly(aniline) (PANI), poly(thiopene)s, andpoly(9,9-dioctylfluorene co-bithiophen) (F8T2), and combinationsthereof.
 13. The electrode of claim 1, wherein a thickness of theflexible, water vapor-permeable, conductive adhesive material is between0.25 and 50 mils.
 14. The electrode of claim 1, wherein the flexible,water vapor-permeable, conductive adhesive material comprises conductiveparticles.
 15. The electrode of claim 1, wherein the current dispersingelement comprises a metallic wire mesh.
 16. The electrode of claim 15,wherein the metallic wire mesh comprises a metal selected from the groupconsisting of copper, tin, nickel, silver, gold, and combinationsthereof.
 17. The electrode of claim 1, wherein the conductive, currentdispersing element comprises nickel-plated carbon-filled fibers.
 18. Theelectrode of claim 1, wherein the current dispersing element issegmented.
 19. The electrode of claim 1, further comprising a backingattached to the flexible, water vapor-permeable, conductive adhesivematerial.
 20. The electrode of claim 19, wherein the backing extendsbeyond an outer surface of the electrode.
 21. The electrode of claim 1,further comprising a frame provided on an outer surface of thenon-conductive, flexible, water vapor-permeable, electrically-insulatingtop layer.
 22. The electrode of claim 21, wherein the frame is disposedaround the perimeter of the electrode.
 23. A therapeutic currentdelivery system comprising: a therapeutic current delivery device; atleast one cable connector connected to the therapeutic current deliverydevice; and at least one electrode connected to the at least one cableconnector, wherein the at least one electrode comprises: a flexible,water vapor-permeable, conductive adhesive material; a currentdispersing element in contact with the conductive adhesive material; anda non-conductive, flexible, water vapor-permeable,electrically-insulating top layer provided in contact with the currentdispersing element; wherein the current dispersing element is conductiveat least laterally along a plane of the electrode; and wherein theconductive adhesive material is conductive in a direction substantiallyorthogonal to the plane of the electrode and semi-conductive in adirection substantially lateral to the plane of the electrode.
 24. Thesystem of claim 23, wherein the cable connectors are no more than 10inches long.
 25. The system of claim 23, wherein the therapeutic currentdelivery device is a defibrillation device.
 26. The system of claim 23,wherein the therapeutic current delivery device is a pacing device. 27.The system of claim 23, wherein the therapeutic current delivery deviceis a nerve stimulation device.
 28. An electrode for use with atherapeutic current delivery system, comprising: a flexible, watervapor-permeable, conductive adhesive material; a current dispersingelement in contact with the conductive adhesive material to receive atherapeutic current from a connector and distribute the therapeuticcurrent over a plane of the electrode; and a non-conductive, flexible,water vapor-permeable, electrically-insulating top layer in contact withthe current dispersing element; wherein the conductive adhesive materialis conductive in a direction substantially orthogonal to a plane of theelectrode and semi-conductive in a direction substantially lateral tothe plane of the electrode.
 29. The electrode of claim 28, wherein thewater vapor permeability of the electrode is greater than 100 gm/m²/24hours.
 30. An electrode for use with a therapeutic current deliverysystem, comprising: a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer; and a flexible, watervapor-permeable, conductive adhesive material disposed on one side ofthe electrically-insulating top layer, wherein the conductive adhesivematerial configured to provide conductive paths in both lateral andorthogonal directions to a plane of the electrode, wherein the electrodeis configured to deliver a defibrillation pulse comprising a therapeuticpulse having an energy of at least 200 joules.
 31. The electrode ofclaim 30, wherein the top layer is in contact with the conductiveadhesive material.
 32. An electrode for use with a therapeutic currentdelivery system, comprising: a non-conductive, flexible, watervapor-permeable, electrically-insulating top layer; and a flexible,water vapor-permeable, conductive adhesive material disposed on one sideof the electrically-insulating top layer, wherein the conductiveadhesive material configured to provide conductive paths in both lateraland orthogonal directions to a plane of the electrode, wherein theelectrode is configured to deliver at least one pacing pulse comprisinga current pulse having a duration in a range of 10-40 ms and anamplitude of at least 50 mAmps.
 33. An electrode for use with atherapeutic current delivery system, comprising: a non-conductive,flexible, water vapor-permeable, electrically-insulating top layer; anda flexible, water vapor-permeable, conductive adhesive material disposedon one side of the electrically-insulating top layer, wherein theconductive adhesive material configured to provide conductive paths inboth lateral and orthogonal directions to a plane of the electrode,wherein the conductive adhesive material comprises conductive particlesdistributed in a polymer material to provide the conductive paths. 34.An electrode for use with a therapeutic current delivery system,comprising: a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer; and a flexible, watervapor-permeable, conductive adhesive material disposed on one side ofthe electrically-insulating top layer, wherein the conductive adhesivematerial configured to provide conductive paths in both lateral andorthogonal directions to a plane of the electrode, wherein theconductive adhesive material is configured to substantially distribute atherapeutic current over the plane of the electrode prior to delivery toa subject.
 35. An electrode for use with a therapeutic current deliverysystem, comprising: a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer; a flexible, water vapor-permeable,conductive adhesive material disposed on one side of theelectrically-insulating top layer, wherein the conductive adhesivematerial configured to provide conductive paths in both lateral andorthogonal directions to a plane of the electrode; and a currentdispersing element in contact with the conductive adhesive material andconfigured to be conductive at least laterally along the plane of theelectrode.
 36. An electrode for use with a therapeutic current deliverysystem, comprising: a non-conductive, flexible, water vapor-permeable,electrically-insulating top layer; and a flexible, watervapor-permeable, conductive adhesive material disposed on one side ofthe electrically-insulating top layer, wherein the conductive adhesivematerial configured to provide conductive paths in both lateral andorthogonal directions to a plane of the electrode, wherein the watervapor permeability of the electrode is greater than 100 gm/m²/24 hours.